This invention relates to a medical diagnostic ultrasound system and method for scan plane orientation. In particular, graphics, annotation, and/or ultrasound image orientation for visualizing the location and orientation of a scan plane within a patient are provided.
Ultrasound images represent anatomical structure within a body. As typically displayed, the ultrasound image is oriented with respect to the transducer such that the portion of the image closest to the transducer is on the top or bottom of the display. Some ultrasound systems allow the user to flip from a transducer up to a transducer down position or vice versa. Minimal operator controls may also be included to allow the operator to flip the image left and right. Regardless of how the orientation of the transducer with respect to the patient changes during the course of an exam, the image orientation is restricted to the transducer up or transducer down orientation. The position of the scan plane with reference to the anatomical structure shown on the ultrasound image is difficult to determine. As a result, the image is difficult to interpret, such as for interpretation by someone not controlling the transducer.
Other medical Imaging methodologies, such as computed tomography (CT) or Magnetic Resonance Imaging (MRI) provide images oriented on the display relative to the body being imaged. For example, transverse or nearly transverse images are presented with the anterior portion of the anatomy at the top, the posterior portion of the anatomy on the bottom, the left portion of the anatomy on the right and the right portion of the anatomy on the left. Coronal or nearly coronal images are presented with the superior portion of the anatomy on the top, the inferior portion on the bottom, the right portion on the left and the left portion on the right. As yet another example, sagittal images are positioned with the superior portion of the anatomy on the top and the inferior portion of the anatomy on the bottom.
Information indicating the orientation of the image with respect to the transducer has been provided for some ultrasound applications. For example, images generated with a transesophageal transducer use icons to indicate the position of the transducer array with respect to the transducer housing. A transverse or a longitudinal icon, such as the letters xe2x80x9cTxe2x80x9d or xe2x80x9cLxe2x80x9d, may be displayed with an image to indicate which of the two transducer planes within the transesophageal transducer are in use. For a multi-plane transesophageal transducer, an angle icon indicating the rotation of the transducer within the probe is provided.
Ultrasound systems have also provided an outline of a torso or head on a display. A dash is then positioned relative to the outline to represent where the transducer was located for obtaining an image displayed on the display in the traditional manner described above.
U.S. Pat. No. 5,797,849 describes tracking various objects within a patient""s body, and imaging the objects as well as the anatomical structure. At column 30, lines 43-50, Vesely et al. describe positioning a pie shaped sector scan into a 3-D scene of the patient. A perspective rendering of a patient frame of reference based on scanning the patient, the location and direction of surgical instruments, and the pie shaped image are then oriented within the scene as shown in FIG. 18 of that patent. FIG. 18 of that patent shows the pie shaped ultrasound sector image in a transducer up position. The 3-D scene appears to have been oriented around the vertically positioned pie shaped sector.
U.S. Pat. No. 5,876,345 also discloses information indicating the placement of the scanned plane relative to the patient""s body. In particular, a transducer up image such as shown in FIGS. 10, 12 and 13 of that patent is shown generated with a linear transducer array. An icon representing a sector as well as a numerical display indicates the position of the two-dimensional image relative to the body. The two-dimensional linear image is statically positioned. FIGS. 11, 12 and 13 of that patent also show a image generated with a radial array of transducer elements on a catheter. The radial image is designated by a circular border or edge with the position of the transducer indicated as a center point. At column 10, lines 30-33, Eaton et al. disclose rotating the radial image display according to the detected rotation angle to compensate for the physical device or transducer rotation. However, the result is different placement of the anatomical structure within the circular image without any change in the placement of the border or the edge of the image.
The present invention is defined by the following claims, and nothing in this section should be taken as a limitation on those claims. By way of introduction, the preferred embodiment described below includes a method and system for displaying ultrasound images. The image is oriented on the display in a manner consistent with the orientation of the anatomy, allowing a physician to more easily interpret the content of the image and relative positions of anatomical structures. The image is rotated away from the xe2x80x9ctransducer upxe2x80x9d position such that a line orthogonal to the transducer face is displayed at an angle away from vertical position on the display. As used herein, the transducer-up position corresponds to an image generated as if the transducer were on the top of the scan plane.
Alternatively or additionally, the relative position of the scan plane and associated image relative to the body is represented by positioning a generic representation of the body relative to the image. For example, the images are displayed in a transducer up or transducer down position, and a wire frame or other representation, such as a three-dimensional wire frame representation, is positioned to indicate the location of the scan plane within the body.
Such orientation information is particularly advantageous for images generated from an array internal to the body. Orienting the image on the display in association with the relative position on the scan plane within the patient may also be valuable for surgeons or other physicians not accustomed to viewing ultrasound images. Likewise, such oriented images allow for more efficient comparison with images generated using other modalities, such as CT or MRI. The image representing anatomical structure may also be displayed with a generic representation of a portion of the body, such as a torso, portion of the torso or an organ, to allow better orientation and relative position determination by the user.
In a first aspect, an improvement is provided for a medical diagnostic ultrasound two-dimensional image representing a two-dimensional region within a body and comprising an edge having at least one point corresponding to a position substantially adjacent to a transducer. The improvement includes orienting the image such that a direction orthogonal to a center of a face of the transducer is at an angle of rotation away from vertical on the display.
In a second aspect, a medical diagnostic ultrasound method for displaying a two-dimensional image is provided. A two-dimensional ultrasound image is generated. The two-dimensional ultrasound image is oriented such that the image appears rotated from a transducer up or down position as a function of the border of the image.
In a third aspect, a medical diagnostic ultrasound system is provided for displaying a two-dimensional image. An ultrasound transducer probe is adapted for use external to a patient to scan a two-dimensional region of the patient. A display is operable to display an ultrasound two-dimensional image representing the two-dimensional region wherein the display is free of three-dimensional representations rendered as a function of a scan of the patient. A controller is operative to orient the two-dimensional image as a function of an angle of the transducer probe relative to the patient.
In a fourth aspect, a medical diagnostic ultrasound method and system for imaging a region of a body are provided. A transducer ultrasonically scans a region of interest in the body. An orientation of the region with respect to anatomical features of the body is monitored, such as with a position sensor or other device. A display displays an ultrasound two-dimensional image responsive to the scan and displays a generic representation of at least a portion of the body wherein the image is geometrically aligned with the generic representation.
Further aspects and advantages of the invention are discussed below in conjunction with the preferred embodiments.